Followers

January 9, 2009

Exercise increases brain function

HEALTH - Regular physical activity such as weightlifting and abdominal exercises is known to improve cognitive ability and help stave off dementia, and now Canadian researchers think they know why.

In a small study of post-menopausal women aged 50 to 90, researchers at the University of Calgary found that those who were aerobically fit had improved blood flow to the brain, and that in turn was linked with better cognitive function.

"Being sedentary is now considered a risk factor for stroke and dementia," said principal investigator Marc Poulin, a physiologist at the University of Calgary in Canada. "This study proves for the first time that people who are fit have better blood flow to their brain. Our findings also show that better blood flow translates into improved cognition."

The study involved 42 women who were divided into active and sedentary groups based on their fitness levels. In part, fitness levels were determined by questionnaires that asked about leisure, household and volunteer activities and their frequency.

To conduct the study, researchers tested the women for oxygen uptake as they exercised on a stationary bike. On a subsequent day, their blood vessel capacity was measured by having them breathe elevated levels of carbon dioxide while at rest.

"This is where we assess the capacity of the blood vessels in the brain to respond to increased demand," Poulin said Thursday from Calgary.

In the same way that a person's heart function is measured using a treadmill stress test, "our idea was to use two tests to give us a sense of the capacity of the brain from a pure physiological level - so ... how the blood vessels work," Poulin said.

On another day, the researchers gave participants a battery of cognitive tests that assessed memory, speed of thinking and the ability to multi-task and problem-solve.

They found that compared to women in the sedentary group, the active group had lower (10 per cent) resting and exercising arterial blood pressure, higher (five per cent) vascular responses in the brain during low-intensity exercise and when carbon dioxide blood levels were raised, and higher (10 per cent) cognitive function scores.

So overall that means exercise lowers your normal blood pressure, more heart power when exercising, and higher cognitive function because of better blood flow to the brain.

So does this mean Americans with obesity are more likely to be stupid? No, but their cognitive functions might be a bit slower. Scientists have already determined obesity is an eating disorder in the brain, but is it possible the high-cholesterol in an obesity patient's blood might be interfering with their cognitive speed?

Maybe. Indeed it might even be contributing to the eating disorder as a whole, making it cyclical and thus solving obesity could be determined by breaking the cycle.

To determine this we would need researchers to conduct an experiment with two groups of people, one athletes and the other obesity patients. Use the same testing process above and determine which has faster cognitive functions.

Then, as part 2 of the test, place the obesity patients on a diet and an exercise regimen and see if they score higher on cognitive functions after a week.